Yes, it would be very very very very very useful to be able to make a pop-up menu both wider and taller than Qt's defaults.

I may have omitted a few "very"s.

In Linux, the upgrade to Qt5 has fixed this issue "for free."

Can other people test OSX and Windows?

w = Window("popup test", Rect(800, 200, 200, 120));
p = PopUpMenu(w, Rect(2, 2, 50, 20))
.items_(Array.fill(15, { |i| "Very long item name" + i }));
w.front;

On my system, the widget is 50 pixels wide and shows only "Very." Clicking on the widget brings up a box that's much wider, and displays the complete strings. Also, Qt5 no longer puts in a scrollbar for >10 items.

Works here on OS X 10.10. I suppose that counts?